Characterisation of neurotransmitter-induced electrolyte transport in cockroach salivary glands by intracellular Ca2+, Na+ and pH measurements in duct cells.

摘要: Ion-transporting acinar peripheral cells in cockroach salivary glands are innervated by dopaminergic and serotonergic fibres, but saliva-modifying duct only fibres. We used microfluorometry to record intracellular Na+, Ca2+ H+ concentrations ([Na+]i, [Ca2+]i pHi) of two types preparation, viz \`lobes' consisting acini with their system \`isolated ducts' without acini, order obtain information about the transporters involved saliva secretion and/or modification. Our results indicate that (1) stimulation lobes dopamine (DA) causes a strong drop pHi increases [Na+]i cells; (2) contrast, DA isolated ducts produces small no changes [Ca2+]i; (3) also induced serotonin (5-HT) lobes, not ducts; (4) absence CO2/HCO3–, DA-induced is strongly reduced removal extracellular Cl– or inhibition Na+–K+–2Cl– cotransporter (NKCC); (5) presence NKCC inhibition, rather Cl–/HCO3– exchanger (AE), Na+/H+ (NHE) carbonic anhydrase. suggest 5-HT act predominantly on cells. Their activity (secretion primary saliva) seems cause ion AE/NHE activities necessary for we consider these NaCl-rich saliva.